447 research outputs found

    Cultivation and Complete Genome Sequencing of Gloeobacter kilaueensis sp. nov., from a Lava Cave in KÄ«lauea Caldera, Hawai'i

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    The ancestor of Gloeobacter violaceus PCC 7421T is believed to have diverged from that of all known cyanobacteria before the evolution of thylakoid membranes and plant plastids. The long and largely independent evolutionary history of G. violaceus presents an organism retaining ancestral features of early oxygenic photoautotrophs, and in whom cyanobacteria evolution can be investigated. No other Gloeobacter species has been described since the genus was established in 1974 (Rippka et al., Arch Microbiol 100:435). Gloeobacter affiliated ribosomal gene sequences have been reported in environmental DNA libraries, but only the type strain's genome has been sequenced. However, we report here the cultivation of a new Gloeobacter species, G. kilaueensis JS1T, from an epilithic biofilm in a lava cave in Kīlauea Caldera, Hawai'i. The strain's genome was sequenced from an enriched culture resembling a low-complexity metagenomic sample, using 9 kb paired-end 454 pyrosequences and 400 bp paired-end Illumina reads. The JS1T and G. violaceus PCC 7421T genomes have little gene synteny despite sharing 2842 orthologous genes; comparing the genomes shows they do not belong to the same species. Our results support establishing a new species to accommodate JS1T, for which we propose the name Gloeobacter kilaueensis sp. nov. Strain JS1T has been deposited in the American Type Culture Collection (BAA-2537), the Scottish Marine Institute's Culture Collection of Algae and Protozoa (CCAP 1431/1), and the Belgian Coordinated Collections of Microorganisms (ULC0316). The G. kilaueensis holotype has been deposited in the Algal Collection of the US National Herbarium (US# 217948). The JS1T genome sequence has been deposited in GenBank under accession number CP003587. The G+C content of the genome is 60.54 mol%. The complete genome sequence of G. kilaueensis JS1T may further understanding of cyanobacteria evolution, and the shift from anoxygenic to oxygenic photosynthesis. © 2013 Saw et al

    European propolis is highly active against trypanosomatids including Crithidia fasciculata

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    Extracts of 35 samples of European propolis were tested against wild type and resistant strains of the protozoal pathogens Trypanosoma brucei, Trypanosoma congolense and Leishmania mexicana. The extracts were also tested against Crithidia fasciculata a close relative of Crithidia mellificae, a parasite of bees. Crithidia, Trypanosoma and Leishmania are all members of the order Kinetoplastida. High levels of activity were obtained for all the samples with the levels of activity varying across the sample set. The highest levels of activity were found against L. mexicana. The propolis samples were profiled by using liquid chromatography with high resolution mass spectrometry (LC-MS) and principal components analysis (PCA) of the data obtained indicated there was a wide variation in the composition of the propolis samples. Orthogonal partial least squares (OPLS) associated a butyrate ester of pinobanksin with high activity against T. brucei whereas in the case of T. congolense high activity was associated with methyl ethers of chrysin and pinobanksin. In the case of C. fasciculata highest activity was associated with methyl ethers of galangin and pinobanksin. OPLS modelling of the activities against L. mexicana using the mass spectrometry produced a less successful model suggesting a wider range of active components

    Pseudoalteromonas piratica sp. nov., a budding, prosthecate bacterium from diseased Montipora capitata, and emended description of the genus Pseudoalteromonas

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    A Gram-stain-negative, motile, rod-shaped bacterium designated OCN003T was cultivated from mucus taken from a diseased colony of the coral Montipora capitata in Kāne‘ohe Bay, O‘ahu, Hawai‘i. Colonies of OCN003T were pale yellow, 1–3 mm in diameter, convex, smooth and entire. The strain was heterotrophic, strictly aerobic and strictly halophilic. Cells of OCN003T produced buds on peritrichous prosthecae. Growth occurred within the pH range of 5.5 to 10, and the temperature range of 14 to 39 °C. Major fatty acids were 16 : 1!7c, 16 : 0, 18 : 1!7c, 17 : 1!8c, 12 : 0 3-OH and 17 : 0. Phylogenetic analysis of 1399 nucleotides of the 16S rRNA gene nucleotide sequence and a multi-locus sequence analysis of three genes placed OCN003T in the genus Pseudoalteromonas and indicated that the nearest relatives described are Pseudoalteromonas spongiae, P. luteoviolacea, P. ruthenica and P. phenolica (97–99 % sequence identity). The DNA G+C content of the strain’s genome was 40.0 mol%. Based on in silico DNA–DNA hybridization and phenotypic differences from related type strains, we propose that OCN003T represents the type strain of a novel species in the genus Pseudoalteromonas, proposed as Pseudoalteromonas piratica sp. nov. OCN003T (=CCOS1042T =CIP 111189T ). An emended description of the genus Pseudoalteromonas is presented

    The First Neptune Analog or Super-Earth with Neptune-like Orbit: MOA-2013-BLG-605Lb

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    We present the discovery of the first Neptune analog exoplanet or super-Earth with Neptune-like orbit, MOA-2013-BLG-605Lb. This planet has a mass similar to that of Neptune or a super-Earth and it orbits at 9∌149\sim 14 times the expected position of the snow-line, asnowa_{\rm snow}, which is similar to Neptune's separation of 11 asnow 11\,a_{\rm snow} from the Sun. The planet/host-star mass ratio is q=(3.6±0.7)×10−4q=(3.6\pm0.7)\times 10^{-4} and the projected separation normalized by the Einstein radius is s=2.39±0.05s=2.39\pm0.05. There are three degenerate physical solutions and two of these are due to a new type of degeneracy in the microlensing parallax parameters, which we designate "the wide degeneracy". The three models have (i) a Neptune-mass planet with a mass of Mp=21−7+6MEarthM_{\rm p}=21_{-7}^{+6} M_{Earth} orbiting a low-mass M-dwarf with a mass of Mh=0.19−0.06+0.05M⊙M_{\rm h}=0.19_{-0.06}^{+0.05} M_\odot, (ii) a mini-Neptune with Mp=7.9−1.2+1.8MEarthM_{\rm p}= 7.9_{-1.2}^{+1.8} M_{Earth} orbiting a brown dwarf host with Mh=0.068−0.011+0.019M⊙M_{\rm h}=0.068_{-0.011}^{+0.019} M_\odot and (iii) a super-Earth with Mp=3.2−0.3+0.5MEarthM_{\rm p}= 3.2_{-0.3}^{+0.5} M_{Earth} orbiting a low-mass brown dwarf host with Mh=0.025−0.004+0.005M⊙M_{\rm h}=0.025_{-0.004}^{+0.005} M_\odot which is slightly favored. The 3-D planet-host separations are 4.6−1.2+4.7_{-1.2}^{+4.7} AU, 2.1−0.2+1.0_{-0.2}^{+1.0} AU and 0.94−0.02+0.67_{-0.02}^{+0.67} AU, which are 8.9−1.4+10.58.9_{-1.4}^{+10.5}, 12−1+712_{-1}^{+7} or 14−1+1114_{-1}^{+11} times larger than asnowa_{\rm snow} for these models, respectively. The Keck AO observation confirm that the lens is faint. This discovery suggests that low-mass planets with Neptune-like orbit are common. So processes similar to the one that formed Neptune in our own Solar System or cold super-Earth may be common in other solar systems.Comment: 54 pages, 10 figures, 13 tables, Accepted for publication in the Ap

    MOA-2016-BLG-227Lb: A Massive Planet Characterized by Combining Light-curve Analysis and Keck AO Imaging

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    We report the discovery of a microlensing planet—MOA-2016-BLG-227Lb—with a large planet/host mass ratio of q ≃ 9 × 10−3. This event was located near the K2 Campaign 9 field that was observed by a large number of telescopes. As a result, the event was in the microlensing survey area of a number of these telescopes, and this enabled good coverage of the planetary light-curve signal. High angular resolution adaptive optics images from the Keck telescope reveal excess flux at the position of the source above the flux of the source star, as indicated by the light-curve model. This excess flux could be due to the lens star, but it could also be due to a companion to the source or lens star, or even an unrelated star. We consider all these possibilities in a Bayesian analysis in the context of a standard Galactic model. Our analysis indicates that it is unlikely that a large fraction of the excess flux comes from the lens, unless solar-type stars are much more likely to host planets of this mass ratio than lower mass stars. We recommend that a method similar to the one developed in this paper be used for other events with high angular resolution follow-up observations when the follow-up observations are insufficient to measure the lens–source relative proper motion
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